i am planning on making a calculator using a 4 by 4 keypad and a 1.8 inch tft display the display and key pad work fine but how should i go about taking 3 or 4 numbers and calculating them in order of operations?

SmapaPurf:

i am planning on making a calculator using a 4 by 4 keypad and a 1.8 inch tft display the display and key pad work fine but how should i go about taking 3 or 4 numbers and calculating them in order of operations?

How do you want to enter numbers? What type of numbers? Integers only? Or floating point with decimal point within the number?

Typically even the simplest calculators have more than 16 buttons, but you have only 16, which are typically intended for digits 0 to 9, *. #, A. B. C, D

How do you want to use your 16 buttons? Please describe in detail!

You will find it a lot simpler to program if the calculator works with reverse Polish notation.